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Most graphical user interfaces are based on the idea that the user interacts with the computer through a keyboard and a single pointing device (mouse, trackball, touchpad, etc). There are however cases where the use of two (or more) pointing devices can be appropriate, as demonstrated by evaluations and systems that feature bi-manual interaction. This plugin makes it possible to control the observation camera's altitude (i.e. the zoom factor) through a second pointing device, such as a trackball, operated by the user's non-dominant hand. It is based on the MPD add-on for ZVTM, which enables programmers to support multiple pointing devices in their ZVTM-based applications. This feature is distributed as a plug-in because its use implies several constraining requirements.



The Bi-manual Interaction Plugin is part of the zgrviewer-plugins package.

Current version: 0.1.1


The bi-manual interaction plugin for ZGRViewer depends on the ZVTM-MPD which itself depends on the Domino library (included in the package) for handling events sent by USB pointing devices that respect the HID protocol. Domino (and thus this plugin) has the following requirements:


Download and uncompress ZGRViewer-BiMan in the parent of ZGRViewer's main directory. This will add the following JAR files to the plugins directory:

and the following file to the lib directory:

It is not necessary to modify your CLASSPATH to include the JAR files located in the plugins directory. These will be automatically detected at launch time and used by ZGRViewer.

There are however a few Linux-specific things to take care of, as explained in the Linux and X section of ZVTM-MPD's mini-HOWTO. Once done, the plugin is ready for use, provided that at least two pointing devices are connected to your computer (at least one of them should be a USB device as only USB devices can be used by this plugin for the non-dominant hand).

Device Settings

Since v0.4.0, ZGRViewer features a new tab in the Preferences window labeled Plugins, which contains a list of all ZGRViewer plugins available on your system. Each plugin can be configued by clickling on its Settings... button.

user preferences panel screenshot

The bi-manual interaction plugin Preferences window lets you:

It is recommended to use a trackball to control the zoom factor, as this device is better suited to this task than a mouse. To a lesser extent, a touchpad is more appropriate than a mouse.

user preferences panel screenshot

Plugin settings are saved at the same time general ZGRViewer preferences are saved (click on the Save button in the main Preferences winwdow).